Azimuth-fitting for mariners&#39; compasses



E. A. SUTER. AZIMUTH' FlTTlNG FOR'MARINERS COMPASSE'S. APPL|CAT10N FILED AUG. 9.191s.

1,401,205 Patented Dec. 27,1921.

ERNEST ALFRED sUTEE, or AliTCOA'lS', MANCHESTER, ENGLANDL;

AZ IMUTH-FITTING FOR MARINE-RS GOMPASSES.

Application filed August 9, 1919. Serial Ito 316, 163.

To' allwkom it may concern:

Be it known that I, ERNEST ALFRED SUTER, a subject ofthe King of Great Britain, and residentjof Ancoatafih/Ianchester, in the county of Lancaster and Kingdom of England, have invented certain new and useful Improved Azimuth-Fitting for Mariners Compasses, of which the following is. a specification.

The present invention relates to a compass adjuster or corrector whereby a mariner may ascertain at a glance any compass error or any deviation and adjust it straight away without the necessity of chartroom observation.

The device of the present invention is applicable directly to any compass bowl. It consists of a frame adapted to move around the compass bowl on suitable guides which may be partly formed of the rim of the bowl itself. This frame carries a graduated are preferably detachable and a pair of pointers one being adapted to cooperate with the compass card and the other cooperating with the said scale or arc.

The invention is more particularly described with reference to the accompanying drawings in which Figure 1 is a plan view of the device attached to a compass.

Fig. 2 is a perspective view of the device while Fig. 3 is a section on the line 22 of Fig. 2.

A compass 5 with its card 6 of any known construction has mounted upon it the device of the present invention consisting of a frame of brass or other suitable non-magnetic material having a central box 8 having arms 9, 10 and 11. The arms 9 and 10 are connected by an are shaped strip 12 which projects beyond and conforms to the periphery of the compass bowl while grooves 13 and 1 1 are arranged on the arm 11 and are 12 respectively to conform to the contour of the bowl 5 and engage to the rim of this so that the device can be adjusted around the rim of the bowl coaxially with the compass card but the device is held against lateral movement.

A graduated arc, which may be of metal,

Specification of Letters Patent.

PatentedDec. 27, 1921.

but which is entopal glass 15, is secured at its ends to the arms 9 andlO by means of adjusting screws 16. The graduations on the arc range from: thecenter line shown at 17 on the drawing.

both right and left from 0 to east and west areshown in Figs. 1 and 2. This arc is preferably detachable so that either a metal are or a transparent are for use at nlght can be set up on the device.

In use to determine any deviation in the compass needle from the correct position a horizon glass 19 is mounted on a pivot carrled in standards 21, projecting upwardly and centrally off the are shaped strip 12. The llOIlZOIl glass is arranged to receive the suns rays as reflected from the index glass 20 pivoted between standards 22 on the arm 11. The index glass 20 and horizon glass 19 are manipulated by means of milled heads 26 and 27 on their respective pivots. If desired a colored shade 23 pivoted to the standards 22 may be swung into position in the light ray path.

A pointer 25 recording the true bearing is mounted to be freely rotatable about a spindle 28 projecting upwardly from the bottom of the hub 8. The lower end of the spindle 28 is pointed and protrudes downward and is used for pivoting on the center of the compass.

A second pointer 29 is adapted to indicate the variation of the compass on the are 15 and is mounted on a fixed spindle 39 depending centrally from the top of the hub or box of the device in alinement with the stub 28. These pointers 25 and 29 are manipulated by means of thumb screws 30 and 31 connected to shafts 32 and 33 the ends of which have mounted gears 34 and 35 meshing with gears 36' and 37 carried by'the respective spindles 28 and 39 of the pointers.

The longest pointer 25, is set to the true bearing (taken from tables) on the compass card, the observed bearing being registered by the reflected sun, star, or other object on the center line by the horizon mirror 19. This is the error which is named on the arc. The other or shorter pointer 29 is then set to indicate the variation on the arc. The difference between the two pointers preferably of white transparshown on the arc is the deviation. As an example A bearing taken by'azimuth of the sum.

True bearing N. 73 east Observed bearing N. 75 east Error 2 west Variation 14 west Deviation; 12 east 2. A compass corrector comprising a. frame a graduated are carried by said frame, means to mount said frame on a compass bowl so that said are and compass card will be concentric, a pair of needle pointers pivoted in the frame and cooperating with said are and with thecompass card, one to indicate the true bearing and the other to indicate the compass error as a direct reading, coaxial spindles mounted in the frame and respectively carrying said needle pointers, a separate operating head for each spindle and gearing connecting each head with one of said spindles.

In witness whereof, I have hereunto signed my name this 16th day of July, 1919, in the presence of two subscribing witnesses.

r r r ERNEST ALFRED 'SUTER. 'Witnesses: f Y J ROBERT F. SANDERSQN, HERBERT HoUGH'roN. 

